Magnetoresistance and spin polarization in the insulating regime of a Si two-dimensional electron system

We have studied the magnetoresistance in a high-mobility Si inversion layer down to low electron concentrations at which the longitudinal resistivity $\rho_{xx}$ has an activated temperature dependence. The angle of the magnetic field was controlled so as to study the orbital effect proportional to the perpendicular component $B_\perp$ for various total strengths $B_{\rm tot}$. A dip in $\rho_{xx}$, which corresponds to the Landau level filling factor of $\nu=4$, survives even for high resistivity of $\rho_{xx} \sim 10^8 \Omega$ at $T= 150 {\rm mK}$. The linear $B_{\rm tot}$-dependence of the value of $B_\perp$ at the dip for low $B_{\rm tot}$ indicates that a ferromagnetic instability does not occur even in the far insulating regime.Comment: 6 pages, 7 figures, submitted to PR

Feasibility of a geothermal direct use enterprise park in Puna, Hawaii

"After a public information process which included surveying community members regarding the acceptability of 21 different geothermal direct use applications, four agriculture-related businesses were selected as candidates for a hypothetical 15-acre (6 ha) geothermal enterprise park in the Kapoho/Pohoki area of the island of Hawaii. The applications included greenhouse bottom heating, pasteurization of potting media, biodiesel production, and lumber drying. There was significant community support for the chosen applications, and minimal opposition expressed. An engineering analysis concluded that a direct use enterprise park is technically feasible. Such a park could require up to 11 million Btu/hr (770 kcal/sec) of heat which might be supplied from a high-temperature resource, such as waste heat from a power plant, causing less than a 10° F (5.6° C) decrease in injectate temperature. The analysis was based on this hypothetical scenario, since waste heat is not currently available for direct use. The direct use enterprise park would cost an estimated $12.5 million to develop and construct, and$738,000 per year to operate and maintain. The hypothetical park would only be marginally economically viable, even with significant financial subsidies. Annual revenues are expected to be $1.21 million, based on a$200/acre annual lease rate and a geothermal heat rate priced at $1.32/therm, or half of the prevailing average cost of diesel and propane. Annual revenues could be as high as$2.42 million if the geothermal heat was priced the same as conventional fuels. The geothermal applications in the park could be expected to replace the use of 6,500-9,700 barrels of crude oil each year. In addition, 130 new jobs could be created.

Intravascular stent motor powered by ultrasonic irradiation

We have developed a stent motor that can move in the blood vessel by applying the technique of the ultrasonic motor. First, we have designed a horn to provide ultrasonic energy to the stent from outside of human body. Second, we have also designed a stent motor that consists of two parts; a stator and receivers. The receiver unit obtains the ultrasonic wave from outside. The stator is the coil shape and it can move smoothly in intravascular. Finally, we have made experiments by the horn and stent motor. We have succeeded in driving the stent motor back and forth in the water

Development of ultrasonic motor with a coil type stator and its application to vascular endoscope

IVUS (Intravascular Ultrasound) is a useful medical device to observe the thrombus in blood vessels, and such a micro motor less than 1.0 mm in outer diameter is desired to apply IVUS in narrow brain vessels. In our previous works, ultrasonic motor consisting of a wire coil type stator, a waveguide, a cylindrical rotor, an ultrasonic vibrator has been developed. This motor is rather easy to miniaturize because of its simple structure. However, this motor behavior is unstable rotate. To improve these problems, a foil type stator has been applied in stead of a wire coiled stator. An ultrasonic motor with 0.05 mm thick foil type stator was manufactured and tested their performances. It was able to verify that this ultrasonic motor with a foil type stator has the right quality. So, simplified IVUS system using ultrasonic motor with a foil type stator was manufactured and tested their fundamental performances. In order to expand development of new application, ultrasonic motor with a shortened waveguide and ultrasonic motor integrated driving unit with a stator was developed

Guided Unfoldings for Finding Loops in Standard Term Rewriting

In this paper, we reconsider the unfolding-based technique that we have introduced previously for detecting loops in standard term rewriting. We improve it by guiding the unfolding process, using distinguished positions in the rewrite rules. This results in a depth-first computation of the unfoldings, whereas the original technique was breadth-first. We have implemented this new approach in our tool NTI and compared it to the previous one on a bunch of rewrite systems. The results we get are promising (better times, more successful proofs).Comment: Pre-proceedings paper presented at the 28th International Symposium on Logic-Based Program Synthesis and Transformation (LOPSTR 2018), Frankfurt am Main, Germany, 4-6 September 2018 (arXiv:1808.03326